Conventional methods for distinguishing individual characteristics in a group typically use a camera and facial recognition software. Conventional image-based methods suffer because many images are not taken with a sufficiently high resolution for use by the facial recognition software. Further, face recognition typically requires a tedious registration process involving taking a large number of pictures for each user, and does not function accurately due to variations in user's face orientation, lighting conditions or occlusions caused by nearby users or objects. Other conventional methods involve locating individuals using radio frequency (RF) devices, but because such devices utilize signals having a long wavelength, such devices cannot sufficiently localize the signals so as to distinguish members within a group.